function diff = delta_OJS(m,param)
    % delta(m) under C=0 in hiring region
    delta_1 = (param.r + param.zeta + param.s.*param.lambda + param.omega_0./param.c).*param.m_h^(-1./(1-param.alpha)) ...
        - (1-param.omega_1)./param.alpha./param.c.*param.m_h^(1-1./(1-param.alpha));
    diff = (1-param.omega_1)./param.alpha./param.c.*m ...
        -(param.omega_0+(param.r + param.zeta).*param.c)./param.c+delta_1.*m.^(1/(1-param.alpha));

end 